Process and installation for the production of stiff recyclable sandwich-type polymeric panels, without the use of adhesives, and the panel produced

A process for the continuous production of a stiff polymeric foamed sheet, comprising the following steps:

• a) contacting a polymeric mass and other components of a mixture in an extruder of a first assembly line;
• b) producing a foamed sheet (5) by extrusion, such that foaming begins at an outlet of an extrusion head, wherein the extrusion head is a multi-channel head and includes a T-shaped material distributing channel, a plurality of distributing channels downstream from the T-shaped material distributing channel, the plurality of distributing channels having a smaller cross section than the T-shaped material distributing channel, and wherein the plurality of distributing channels are connected to additional multiple channels having cross-sections that are smaller than cross-sections of the plurality of distributing channels, and wherein the outlet includes a restricting bar and flexible opening lips, so as to gradually increase pressure on the mixture until the mixture reaches the lips of the outlet;
• c) calibrating the foamed sheet;
• d) cooling and drawing the foamed sheet so as to form a foamed core;
• e) producing structural skins in a second assembly line separate from the first assembly line;
• f) feeding the foamed core (5) and the structural skins (55) into a third assembly line;
• g) attaching the structural skins (55) to the foamed core (5) by heat and pressure to form sandwich panels in the third assembly line;
• and
• h) longitudinally and transversely cutting the sandwich panels to predetermined dimensions.